The present invention relates to a semiconductor integrated circuit device necessitating a boosted voltage which is boosted from a power source voltage or the like, particularly to a voltage boosting circuit generating the boosted voltage.
Further, the present invention relates to electronic apparatuses to which the semiconductor integrated circuit device is integrated with regard to a method of utilizing the semiconductor integrated circuit device in an electric circuit.
FIG. 28 shows a schematic sectional view of a conventional MOSFET. The MOSFET formed on a semiconductor substrate 4 is constituted by a source 2, a drain 3, a channel 9 between the source 2 and the drain 3, a gate insulating film 8 formed on the channel 9 and a gate 1 and an impurity concentration of the channel 9 is equal to or more than 5.times.10.sup.15 atoms/cc.
In a voltage boosting circuit using the conventional MOSFET, the threshold is increased by the body effect of the MOSFET by which the voltage boosting efficiency is considerably deteriorated. Further, the higher the desired voltage, the more considerable is an increase in the threshold due to the body effect of the MOSFET and, therefore, a semiconductor integrated circuit device having a voltage boosting circuit with high function, high efficiency and low cost could not be provided.